Semi-automatic machines for chill casting
hollow parts such as pistons



Nov. 8, 1966 L PERAS 3,283,374

SEMI-AUTOMATIC MAI-IINES FOR CHILL CASTING HOLLOW PARTS SUCH AS PISTONS Filed March 30, 1964 7 Sheets-Sheet 1 Nov. 8, 1966 PERAS 3,283,374

L. SEMI-AUTOMATIC MACHINES FOR CHILL CASTING HOLLOW PARTS SUCH AS PISTONS Filed March 30, 1964 7 Sheets-Sheet 2 1 L. PERAS 3,283,374

SEMP-AUTOMATIC MACHINES FOR CHILL CASTING HOLLOW PARTS SUCH-AS PISTONS Filed March 30, 1964 7 Sheets-Sheet 3 Nov. 8, 1966 1.. PERAS SEMI'AUTOMATIC MACHINES FOR CHILL CASTING HOLLOW PARTS SUCH AS PISTONS 7 Sheets-Sheet 4 Filed March 30, 1964 Nov. 8, 1966 PERAS 3,283,374

L. SEMI-AUTOMATIC MACHINES FOR CHILL CASTING HOLLOW PARTS SUCH AS PISTONS Nov. 8, 1966 L. PERAS SEMI"AUTOMATIC MACHINES FOR CHILL CASTING HOLLOW PARTS SUCH AS PISTONS 7 Sheets-Sheet 6 Filed March 30, 1964 Nov. 8, 1966 PERAS 3,28

SEMI-AUTOMATIC HINES FOR CHILL CASTING HOLLOW PARTS SUCH AS PISTONS Filed March 50, 1964 '7 Sheets-Sheet 7 V f i IL 74 l i l, i 3 g \W \HHHHHHI United States Patent French works Filed Mar. 30, 1964, Ser. No. 355,729 Claims priority, application France, Apr. 5, 1963,

930,65 8 Claims. or. 22-93 This invention relates to semi-automatic machines for chill casting parts comprising a cavity which embodies a narrowed portion requiring the use of a core consisting of a plurality of movable core elements. The latter are held close together whereby to have a minimum crosssection' during the stripping operation, and a mutually spaced position during the casting operation. For performing the latter operation a retractable key is inserted between the core elements and contributes therewith to the formation of a core whose outer shape matches that of the cavity it is desired to form within the casting. In such well known machines, closure and opening of the die, engagement and withdrawal of the key, spreading and contracting of the core elements, moving said elements into their operative position and completely or partially withdrawing the same, are all accomplished by means of as many reciprocating motion engendering power devices as there are components to be actuated.

Automatic or semi-automatic operation of the machine is obtained through the agency of actuating means'triggered by synchronising or time-delaying devices.

Since the power devices are usually pneumatic actuators, consecutive operation thereof is controlled by electromagnetic valves of any convenient type controlled by limit or cam-operated microswitches.

These devices, however, have the disadvantage of requiring scrupulously correct adjustments which are diflicult to make, of being fragile, of being prone to go out of adjustment to a considerable extent and of permitting only a comparatively slow production rate due to the multiplicity of actuators, electromagnetic valves and contacts, not to mention the added delay resulting from the time-lags involved in actuator and valve response.

The present invention considerably mitigates these drawbacks by enabling the number of power devices and control means thereof to be reduced. A machine according to this invention permits of operating the key, spreading, contracting, and inserting and withdrawing said care elements into and from the die, by means of a single actuator only, all the operations referred to precedingly being performed by purely mechanical direct-acting transmission means. 1

A semi-automatic machine according to this invention comprises movable core elements whose ends remote from the die are extended by an actuating heel. These elements are kept spread apart during the moulding operation and contracted toegther during the stripping operation. Mounted on a sliding key support is an extended retractable key adapted to be translated longitudinally of itself between a position wherein it is positively engaged between the core elements during casting and a position wherein it is retracted therefrom during stripping. A reciprocating actuator is fixed to the machine in such manner that its moving member be capable of operating on the key through the medium of the key support and of pushing it from its retracted position into its operatively engaged position. Essentially, such a machine is characterized by the fact that provision is made thereon for a device which, during operation of the machine, continuously urges said core elements towards their spreadopen position. To each such element is assigned a bellcrank lever which is fulcrumed on. the machine in such manner as to enable one of its arms to exert pressure on the actuating heel of the core element whereby to urge the same .into the core contracting position when, on reaching the end of its retraction stroke, the key support exerts a force on the other lever arm through the medium of a draw link common to all the bell-crank levers.

These and other features of the invention will become apparent from the description which follows, with reference to the accompanying non-limitative exemplary drawings, of a machine according to the invention adapted to the manufacture of internal combustion engine pistons.

Referring to the drawings filed herewith:

FIGURES 1 through 4 are schematic sectional illustrations of the die and the core with its key, in their respective consecutive positions during operation of the machine; I FIGURE 5 schematically illustrates the manner of op eration of the mechanism for controlling the mutual contraction of the core elements;

FIGURES 6 and 7 schematically illustrates the device for spreading open the core elements;

FIGURE 8 is a front elevation view of the machine;

, FIGURE 9 is a sectional side elevation view of the left half of the machine;

. FIGURE 10 is a front elevation view of the right half of the machine;

FIGURE 11 shows in section through the line XIXI of FIGURE 10 the core element spreading device and the key support;

FIGURE 12 shows in section through the line XII-- XII of FIGURES 9 and 10 a core-bearing device;

FIGURE 13 is a sectional view of the left side of the machine; and

FIGURE 14 is a section taken through the line XIV -XIV of FIGURE 13, showing the mechanism for controlling contraction of the core elements.

In what follows, whenever reference is bad to machine components comprising two parts which, though not identical, are similar and symmetrically disposed to either side of the symmetry plane of the machine, these two parts will invariably be designated by the same reference numeral.

Reference will first be had to FIGURES 1 through 8 for a description of the general principle underlying the machine according to the present invention.

FIGURE 1 shows the die without its actuators and control members, the core and the core-bearing device, the key and its sliding key support, and the upper portion of the mechanism for controlling contraction of the core elements.

The die is made up of two separable halves comprising, from top to bottom, a'pouring cap 1 with its pouring hole 2 and a casting block 3. Through each half of the casting block is slidable a rod 4 whose extremity 5 extends into a chamber 6 whose shape matches that of the piston to be cast. These rod extremities are designed to form the gudgeon pin bearings in the piston.

Cap 1 and block 3 are horizontally slidable along the base structure of the machine (not shown), which structure supports two double-acting actuators for controlling movement of each half-die and thereby enabling the die to be opened and closed. Each half of the pouring cap 1 is rigidly connected to a movable reinforcement 7 to which are likewise secured the rod 4 and the outer extremity of the corresponding actuator plunger rod. These parts are adapted to translate with respect to, and in the same direction as, the corresponding half of the casting block, such translation being limited in each direction by stop means (not shown).

The core is composed of two identical core elements 8, each comprising a cavity 9 matching the shape of the. gudgeon pin bosses. Each core element is extended downwardly by anactuating heel 10 which invariably. remains outside the die. 'The lower portion ofthe ac tuating heel is secured to a part 11 through the agency of which itis pivotally connected, about a shaft 12, to a core-bearing device 13,thereby enabling the core elements to swing away or towards each other in the plane containing the axes of rods 4. A spreader spring (not shown) continuously urges the core elements 8 away from each other.

When the die is .in the closed position, locking toes 14 engage on eachsid'e of the machine beneath flanges 15 on the core-bearing device 13.

Beneath the casting blocks a plate 16 rigid with the machine base structure embodies a central passage lined I witha locating bush 17 which also performs the func-v tion of a sealing member during the casting operation and through which extend the actuating heels 10.

A long vertical central key 18 has one of its ends fixedly secured to a key support 19 which is vertically l slidable through the base structure.

Said key support 19 is movable in both directions by a double-acting hydraulic or pneumatic vertical actuator (not shown) j and raises the key 18 into an operatively engaged position between core elements 8 (which are spread'open prior to pouring) and lowers it into the retracted position for the stripping operation. In its operatively engaged position, the upper end of key 18 and. the two is a horizontal passage extending through plate 16 and locating bush '17, parallel with the axis of rods 4, .and serving as guide means of a pushrod 21. One end of pushrod 21 terminates in a roller 22 rotatable on a horizontal pin parallel'with the symmetry plane of the machine and against which the corresponding actuating heel 10 is applied in pressure contact by the spreaded spring referred to precedingly. Engaging into a recess 23 provided on the lower face of the other end of pushrod 21 is a cog 24 provided on the tip of the upwardly directed upper arm 25 of a bell-crank lever fulcrumed on a splined shaft 26 rotatably mounted in the base structure.

The pushrods 21 and bell-crank levers hereinbefore referred to form part of the mechanism for moving the core elements 8 towards each other, which mechanism is schematically illustrated in FIGURE 5.

Reference to FIGURE 5 clearly shows the core elements 8 and their actuating heels 10 maintained in pressure contact against the rollers 22 of pushrods 21 by a suitable spring (not shown). Two bell-cranks 27 are angularly rigid with splined shafts 26 pivotally supported in convenient base structure bearings. Each bell-crank has an upwardly directed upper arm 25 terminating in said cog 24 engaging into recess 23 of pushrod 21,'and a substantially horizontal arm which, for greater clarity, will hereinafter be referred to as horizontal arm 28.

Horizontal arms 28 are convergent and their ends are slidably pivoted on the upper end of a vertical drawlink 29 disposed in the plane'of symmetry of the machine.

Draw-link 29 is guided in the base structure and has its lower extremity connected to abutment pieces 30 positioned along the path 31 of the pegs of key support 19. A spring 32, whose lower extremity bears against a horizontal bed plate 33 through which extends draw-link 29 and whose upper extremity thrusts against a shoulder portion of draw-link29, continuously urges I the core-bearing device and the core in the upper'most the latter upwardly, whereby pushrods 21 tend to recede from each other.

The general arrangement of the subject machine of the invention, as adapted for the manufacture of pistons, will be clearly apparent from the schematic illustration of FIGURE 8 in which may be recognized the main 1 component parts referred to hereinabove.

Referring now to FIGURE 8, the base structure 34 is seen to support the various component parts and to have fixed thereto two double-actinghorizontal actuators 35 controlling opening and closure of the die, and

a double-acting central actuator 36 which alone controls both raising and lowering of the key support 19 with itskey 18 and the mechanism controlling the, mutual closing motion of core elements 8.

FIGURE 8 also shows such control members as the electromagnetic valves and limit switches ensuring automatic sequence operation, the precise functions of which members will be described hereinafter.

The manner of operation of a machine according to the invention willbe manifest from FIGURES 1 through 4, which show the consecutive functional configurations.

In the positionzshown in FIGURE 1, pouring has just taken place and the metal of piston 37 fills the chamber 6 bounded by casting block 3 and pouring cap 1. The ends 5 of rods 4 are engaged into the internal piston bosses occupying the core cavities 9. The rollers 22 on the ends of pushrods 21 are kept spaced from actuating heels 10 by the influence of spring 32 on draw link 29 and bell-cranks 27 (see FIGURE 5). Key support 19 and key 18 are in their upper-most position and the lock ing toes 14 rigid with movable reinforcement 7 restrain position.

FIGURE 2 shows the next phase. The die is still closed and central actuator 36 (FIGURE 8) has moved key support 19 downwardly, thereby withdrawing key 18 r from the space between core elements 8 while the latter remain in mutually spaced relation under. the urge of the spreader spring (not shown). On reaching the end of its stroke, key support 19 exerts pressure through its vertical pegs 20 onthe abutments 30 of draw-link 29, against the countering force of spring 32 (FIGURE 5). This causes the draw-link to be moved downwardly and to thereby pivot levers '27 (see FIGURE 5), which overcome the force of the spreader spring and apply the core elements 8 .against each other through the medium of pushrods 21. In moving towards each other thus, the core elements release the bosses of piston 37 from the matching cavities 9.

Reference to FIGURE 3 shows that the horizontal actuators 35 (see, FIGURE 8) have operated tofirstly spread open the two halves of pouring cap 1 and the two rods 4, while the remaining machine components are in the position shown in FIGURE 2.

As they complete their retracting motion, movable reinforcements 7, after, covering the first part of their stroke,

displace the two halves of casting block 3 through an equal distance, thereby causing the locking toes 14 rigid with said reinforcements to release the flanges 15 of core-bearing device 13. The latter then descends by gravity until it butts against stop means (not shown) and pulls with it the core elements 8, if not clear of piston 37 in any event Two substantially horizontal spreader beam-levers 39 are each fulcrumed on the core-bearing device 13 through the agency of a rotating yoke 40 enabling the lever to be oriented into either of two mutually perpendicular planes. Disposed substantially in parallelism with the plane of symmetry of the machine, each lever end emerging from the machine is equipped with an operating grip 41. The other end of each lever is slidably pivoted at 42 onto the lower extremity of the corresponding pivotal member 11, each of which members has fixed thereto the actuating heel of a'core element 8.

The spreader spring 43 is anchored between the lever arms bearing the grips 41 and tends to move the same away from each other and hence to move the sliding pivots 42 and the lower extremities of pivotal members 11 towards each other. Since FIGURES 1 through 4 show the actuating heels 10 to be pivotally connected to shafts 12, it follows that the core elements 8 will be continuously urged into mutually spa'ced relationship by spreader spring 43.

Where necessary, operating grips 41 permit of moving the core elements 8 towards each other manually.

Two vertical hooks 44 pivotally connected to base structure 34 each comprise a horizontal stop 45 positioned vertically beneath a lever arm bearing an operating grip 41, which stops limit downward travel of core-bearing device 13.

FIGURES 6 and 7 additionally com-prise, illustrated in diagrammatic fashion, a number of features which will be described in greater detail hereinbelow with reference to FIGURES 9 through 14. These figures clearly reveal certain constructional details of the automatic machine for casting internal combustion engine pistons, which machine is described by way of example only and not of limitation, it being cleanly understood that the present invention likewise encompasses such constructional details.

As may be clearly seen from FIGURES 9, 10 and 13, the base structure 34 (FIGURE 8) comprises a rear support 46 fixed to a convenient stand (not shown). Mounted on the lower part of rear support 46 is horizontal plate 33 and, on its upper part, plate 16. Two guide columns 47 acting as spacers between plate 16 and horizontal plate 33 serve to reinforce the base structure and to guide the core-bearing device 13 and the key support 19 in their vertical movements. On either side of the machine, parallel with its plane of symmetry, two cheeks 48 are mounted on the extremities of two horizontal bars 49 supported by plate 16. The horizontal actuators 35 are secured to said cheeks 48, while central actuator 36 is mounted on horizontal plate 33.

The movable reinforcements 7 connected to the pouring cap 1 and the casting blocks 3 slide along said horizontal bars 49. Pouring cap 1 is fixedly mounted on the movable reinforcements 7, while casting block 3 is displaceable with a degree of endwise play in the same direction as pouring cap 1 and reinforcement 7. This play is limited in one direction by two adjustable stops 50 provided on pouring cap 1 and which, during closing movement of the die, cooperate with bearing surfaces provided on the outer surfaces of the casting block (see FIGURE 9). In the die opening sense, it is the heads 51 of screws 52 screwed into the casting blocks 3 and sliding in passageways embodied in the movable reinforcements 7 which bear against the edge of said passageways and are thereby pulled along by the reinforcements (see FIGURES 10 and 13).

The core-bearing device 13 slidably mounted, on the guide columns 47 includes all the parts precedingly referred to in the description of the underlying principle of the machine described herein by way'of example.

Said device may be equipped in addition with a mechanism for positioning distance pieces 53 inserted into the piston bosses, said distance pieces embodying a hole for the gudgeon pin and being made of a metal different from that poured into the die.

This positioning mechanism is shown in side elevation 6 and in section in FIGURES 9'and 11, in horizontal section in FIGURE 12 and in diagrammatic fashion in FIGURES 6 and 7. It comprises two locking rods 54 each extending through the full length of a passageway 55 provided in the lower parts of core elements 8 and in their actuating heels 10. These rods have their lower ends secured to the sliding pivots 42, while their other ends are so devised that they project into the cavity 9 of each core element 8 and hold a distance piece 53 clamped between the latter-mentioned rod end and the upper wall of cavity 9. Each of two springs 56 accordingly thrusts a pushrod 57 upwardly against the inner arms of spacer beam-levers 39 and thereby exerts a likewise upwardly directed pressure against said rods.

In order to position the distance pieces 53, operating grips 41 are raised whereby to lowerthe upper ends of locking rods 54; the distance pieces are then located between said upper end and the upper edge of the cavities. 9, after which the grips are lowered once more, whereupon the distance pieces are correctly positioned for the casting operation.

A second pushrod 58 acting in the opposite sense to the first pushrod 57 and actuated by a mechanical, electromagnetic, hydraulic or pneumatic control system (not shown), may be provided for retracting the upper ends of locking rods 54 from the cavities 9 or the piston bosses without the need to use the operating grips 41.

As is clearly apparent from the sectional view of FIG URE 12, the front face of core-bearing device 13 comprises a cover 59 having thereon two lugs 60 in which rotate the vertical pins 61 of yokes 40.

As the core-bearing device 13 moves downwardly under gravity as soon as the locking toes 14 fixed to movable reinforcement 7 release the flanges 15 of said core-bearing device, its downward motion is damped by two hydraulic or pneumatic dampers 64. The latter are fixed to the horizontal plate 33, and their plunger rods 65, which extend therethrough, have their extremities fixed to the core-bearing device. Since the other component parts of the core-bearing device designated by their several reference numerals in FIGURES 9 through 13 have been adequately described with respect to their shapes and functions, with reference to the diagrammatic illustrations of FIGURES 1 through 7, any further de-' scription thereof is thought to be redundant.

The key support 19 likewise slides along guide columns 47. The lower end of key 18 forms a heel 66 which is engaged into an inverted T-slot and clamped against the projecting edges of said slot by means of a screwand-wedge device 67 (see FIGURES 9 and ll).

One possible form of embodiment of the mechanism for moving the core elements 8 towards each other is shown in detail in FIGURES 9, l3 and 14.

The draw-link 29 is guided at the bottom by the horizontal plate 33, being slidable through a hole therein,

The upper portion of said link is guided by engagement of an axial peg 68 in a recess provided in the plate 16 supporting the horizontal bars 49. The upper end of the draw-link comprises a pivot member 69 having therein a horizontal bore 70 into which engage the ball-ends 71 fitted to the extremities of the horizontal arms 28 of bell-cranks 27. The pivot member 69 further embodies a vertical cylindrical housing 72 into the lower end of which is screwed a socket 73. A tensile rod 74 is inserted through an axial bore in socket 73, the degree of penetration of tensile rod 74 into the cylindrical housing 72 being limited by an abutment 75 provided in the axial bore of socket 73 and against which butts a corresponding shoulder 76 on tensile rod 74. Spring means consisting of cup washers 77 inserted intermediate the socket 73 and a washer 78 retained by a linchpin on the end of tensile rod 74 maintain abutments 75 and 76 in mutual pressure contact. The spring 32 is fitted under compression between the socket 73 and the horizontal plate 33.

The lower threaded end of tensile rod 74 engages into a central hole 79 provided in a small horizontal strip 80 terminating at each end in a journal 81. A distance piece 82 is positioned between said strip and a nut 83 which is screwed onto the threaded end of the tensile rod and enables the position of said horizontal strip to be adjusted on the tensile rod.

The lower end of tensile rod 74 can be pivoted through cooperation of the journals 81 with notches 84 located at the load-absorbing intermediate point of an end-tub crumed lever 85 whose other end bears the abutment pieces 30 placed in the path of the pegs zoer key support 19 and a pedal 86 for applying a downward elfort on said lever. Lever 85 is fulcrumed about a pin 87 on horizontal plate 33.

Bell-cranks 27 are formed of a plurality of elements by reason of the fact that the opposing loads are exerted in a vertical plane which is perpendicular to the plane of symmetry of the machine and passes through the axis of the die and the key 18, whereas the effort is exerted along the axis of the vertical draw-link 29, which axis is compulsorily located rearwardly of said vertical plane.

The upper arms 25 of bell-cranks 27 are consequently mounted individually on a splined shaft 26 rotating in bearings 88 provided on plate 16. i

The horizontal arms 28 are mounted on the same splined shafts 26, but at a distance equal to that between the axis of draw-link 29 and said vertical plane.

In addition, each of said horizontal arms has a straight section 89 thereof mounted angularly rigid with splined shaft 26, and the bent prongs 90 of a fork 91 are so mounted on said straight section 89 as to enable said fork to rotate about the axis of splined shaft 26. An adjustment screw 92 fitted with a locknut93 is screwed into the straight section 89 in such manner that the end of adjustment screw 92 forms a stop 94 for cooperation with an abutment surface 95 provided between the .two bent prongs, on the bridge-piece of fork 91. This system permits of permanently adjusting the angle subtended by the arms of bell-crank lever 27.

Likewise provided is a second adjustment screw 96 with locknut 97, screwed into each upper arm 25 of hellcranks 27, and the tip of this adjustment screw 96 serves as a stop for cooperating with a vertical abutment face provided on the right and left sides of plate 16 and permits of adjusting the minimum spacing between the core elements -8. The resilient system formed by the cup washers 77 of tensile rod 74 acts as a tensile force limiter capable of otfsetting possible inaccuracies in the adjustment made with the screw 96 with respect to that made with the nut 83 on tensile rod 74.

Semi-automatic operation of the machine hereinbefore described by way of example is obtained in themanner well known per se in the field of industrial automation. As FIGURE'8 clearly shows, it is obtained by means of electromagnetic slide-valves or the like connected into the hydraulic or pneumatic fluid passages of the actuators. The electric power supply circuits for energizing the coils of such electromagnetic valve means comprise suitable switches, pushbutton-operated timers and selec tor switches, and limit switches. The rollers on the pivotal operating levers of the latter are placed in the path of cam-rods rigid with the members displaced by the actuators.

A control slide-valve of the casting block and the pouring cap is equipped with a coil 98 whose energization causes the actuators 35 to be supplied on the sides thereof whereby said casting block and pour-ing cap are opened, and with a coil 99 whose energization causes said actuators to be supplied on the sides thereof whereby said casting block and pouring cap are closed.

A control slide-valve of the key is equipped with a coil 100 whose energization causes the vertical actuator 36 to be supplied on the sidethereof whereby the key support 19 is lowered, and with a coil 101 whose energization causes said vertical actuator 36 to be supplied on the side thereof whereby said key support is raised.

Limit switches 102, 103, 104 and 105 ensure thecorrect sequence of movements of the casting block, the pouring cap and the key and obviate determimental interference with the various operations. A vertical cam-rod 106 is accordingly fixed to the key support 19 (FIG- URES 8, 9 and 11) and embodies, on one side, a notch 107 which operates a limit switch 102 at theend of the downward stroke and, on the other side, a notch 108 which operates the limit switch 103 at the end of the upward stroke.

Likewise, a horizontal cam-rod is mounted on each of the movable reinforcements 7. Thus, the cam-rod 110 operates the limit switch 104 when the casting blocks have opened fully, while the cam-rod 112 operates the, limit switch 105 when said casting blocks have closed fully.

Saidhorizontal cam-rods 110 and 112 are slidably mounted on the base structure and secured to the end 114 of a pushrod 115 (see FIGURES 9 and 10). Pushrod 115 slides in a cylinder 116 fixed to the movable re- 25' inforcemen-t 7 and v is maintained in pressure contact against the casting block 3 by a spring 117 fitted under compression between an abutment face on said pushrod and an annular plug which closes the end of the cylinder. These pushrods 115 not only permit of actuating said horizontal cam-rods but also of opening the pouring cap. 1 before the casting block 3.

Various pushbu-tton boxes enable the various operation to be initiated. I

Pushbutton 118 controls the ascent of key 18,'while simultaneous operation of pushbutton 118 and a pushbutton 119 initiates closure of the casting block and the pouring cap.

Pushbutton 120 .sets 011 a timer which determines the cooling time of the metal in the die. After the preset time-delay has elapsed, this timer. energizes the coil 100 controlling descent of key support'19; When the downward stroke is completed, the notch 108 of cam-rod 106 operates the limitswit-ch 103 which energizes coil 98, thereby causing the casting block and the pouring cap to open.

Obviously, thepiston casting machine hereinbefore described cooperates with plant for supplying molten metal,

which is not covered by the scope of the present invention. The subject machine of the invention enables a high production output of fifty castings per hour to be achieved.

It is additionally feasible to mount a multiplicity of such machines on a turret base and to have recourse to an appropriate automatic plant of known type for pouring the molten metal. The casting operation can then be slaved to the functional characteristics of the machine and be triggered, say, by the casting block and pouring cap closing limit switch 113.

Further, the machine for casting pistonsaccording to the invention is so devised as to enable essential parts prone to Wear to be rapidly disassembled and replaced.

By way of example, the hooks 44 (FIGURES 7 and 10)- acting as limit stops for the core-bearing device 13 are pivotally connected to the base structure and can be tilted laterally by means of levers 121. The abutment 45 then retracts and the core-bearing device 13 descends sufiiciently low to permit easy dismantling and removal of the core.

While there has been shown and described, the preschanically slaved to motion of the key as it reaches the end of its retracting stroke, may lkewise be applied to retractable key adapted to translate longitudinally of itself between an operatively engaged position between the mutually spaced core elements during the casting operation and an inoperative position of: retraction therefrom during the stripping operation being mounted on a slidable key support through the agency of which the movable part of reciprocating translational motion engendering drive means is adapted to push said key from its retracted position to its engaged position, said machine being characterized in that spreader means are provided for biasing during machine operation said core elements towards their mutually spaced position and in that in respect to each of said elements there is provided a bellcrank lever fulcrumed intermediate its ends on the machine in such manner that one of its arms exerts pressure against said actuating heel of the corresponding core element in the sense of moving the same towards the other core elements when on reaching the end of the retracting stroke said key support exerts a force on the other bellcrank arm through the medium of a draw-link common to all the bell-crank levers.

2. A machine as claimed in claim 1 having two core elements and vertical core and key axes, wherein said core element actuating heels are pivotally connected to the machine.

3. A machine as claimed in claim 1 having two core elements and vertical key axes, wherein said core element actuating heels are pivotally connected to the machine to form intermediately fulcrumed levers whose upper ends terminate in core elements, said actuating heels having their other ends urged towards each other by spring means.

4. A machine as claimed in claim 1, wherein said reciprocating translational motion generating drive means is a double-acting actuator whose plunger rod is rigidly united in translation with said slidable key support.

5. A machine as claimed in claim 1, wherein spring means continuously bias said vertical draw-link in the opposite direction to the force exerted by said key support for moving said core elements towards each other.

6. A machine as claimed in claim 1, wherein said bellcrank levers act upon said core element actuating heels through the medium of slidable pushrods.

7. A machine as claimed in claim 1, wherein said core element actuating heels are pivotally connected to a corebearer sliding vertically in the machine and whose upward stroke is limited by an upper abutment and downward stroke by a lower abutment, said core-bearer being so disposed in the path of said slidable key support as to cause the latter to raise said core-bearer during the ultimate portion of its ascending motion in the course of which said key is pushed into its positively engaged posi tion, and being provided with locking means which so cooperate with control means of opening and closure of the die that when the latter opens said core-bearer be released and descend under gravity until it encounters said lower abutment.

8. A machine as claimed in claim 1, wherein the upper end of said vertical draw-link is connected to one of the lever arms of said bell-crank levers through a slidable ball-joint and the lower end pivoted about the intermediate load-absorbing point of an end-fulcrumed lever whose free end which is located in the path of a vertical peg provided on the underside of said slidable key support and which is equipped with a thrust surface or grip whereby said draw-link may be lowered by foot or by hand.

References Cited by the Examiner UNITED STATES PATENTS 2,254,295 9/ 1941 Kohl et al 249-162 2,287,524 6/ 1942 Jackson 22--93 2,521,520 9/1950 Jancura 249162 3,049,768 8/1962 Powell 22-93 I. SPENCER OVERHOLSER, Primary Examiner.

R. D. BALDWIN, Assistant Examiner. 

1. A SEMI-AUTOMATIC MACHINE FOR CHILL CASTING PARTS COMPRISING A CAVITY WHICH HAS A NARROWED PORTION REQUIRING THE USE OF A CORE FORMED OF A PLURALITY OF MOVABLE CORE ELEMENTS SEVERALLY EXTENDED BY AN ACTUATING WHEEL AND MAINTAINED SPACED FROM ONE ANOTHER DURING CASTING AND CLOSE TO ONE ANOTHER DURING STRIPPING, AN EXTENDABLE RETRACTABLE KEY ADAPTED TO TRANSLATE LONGITUDINALLY OF ITSELF BETWEEN AN OPERATIVELY ENGAGED POSITION BETWEEN THE MUTUALLY SPACED CORE ELEMENTS DURING THE CASTING OPERATION AND AN INOPERATIVE POSITION OF RETRACTION THEREFROM DURING THE STRIPPING OPERATION BEING MOUNTED ON A SLIDABLE KEY SUPPORT THROUGH THE AGENCY OF WHICH THE MOVABLE PART OF RECIPROCATING TRANSLATIONAL MOTION ENGENDERING DRIVE MEANS IS ADAPTED TO PUSH SAID KEY FROM ITS RETRACTED POSITION OT ITS ENGAGED POSITION, SAID MACHINE BEING CHARACTERIZED IN THAT SPREADER MEANS ARE PROVIDED FOR BIASING DURING MACHINE OPERATION SAID CORE ELEMENTS TOWARDS THEIR MUTUALLY SPACED POSITION AND IN THAT IN RESPECT TO EACH OF SAID ELEMENTS THERE IS PROVIDED A BELLCRANK LEVER FULCRUMED INTERMEDIATE ITS ENDS ON THE MACHINE IN SUCH MANNER THAT ONE OF ITS ARMS EXERTS PRESSURE AGAINST SAID ACTUATING HEEL OF THE CORRESPONDING CORE ELEMENT IN THE SENSE OF MOVING THE SAME TOWARDS THE OTHER CORE ELEMENTS WHEN ON REACHING THE END OF THE RETRACTING STROKE SAID KEY SUPPORT EXERTS A FORCE ON THE OTHER BELLCRANK ARM THROUGH THE MEDIUM OF A DRAW-LINK COMMON TO ALL THE BELL-CRANK LEVERS. 